Spraying apparatus employing a skirt structure

ABSTRACT

In a new spraying apparatus a spray boom structure supporting the spray dispensers for liquid or finely divided spray material is supported by an air pressured flexible bag skirt attached to the structure and forming an enclosure into which the spray dispensers discharge to minimize drift of the sprayed material and permitting increased speed of the apparatus over the ground. The bag skirt structure also &#34;averages out&#34; irregularities in the surface so that a more uniform spray pattern is achieved. Air is fed into the enclosure from the leading bag skirt part via an elongated aperture close to the ground and from the trailing bag skirt part from an elongated aperture close to the enclosure roof. The weight of the fan and its housing supplying the pressurized air is supported separately from the boom. The boom structure may comprise hinged portions that can be moved to a vertical storage position, and it may also include arcuate downwardly extending support members. The bag skirt structure is supported from the frame consisting of parallel rods and cross-members by loops of material through which the rods pass.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of my prior application Ser.No. 820,110 filed July, 29, 1977, and now abandoned.

FIELD OF THE INVENTION

The present invention is concerned with improvements in or relating tospraying apparatus, and especially to such apparatus employing anair-supported skirt structure.

Review of the Prior Art

Repeated carefully controlled spraying is now an essential part of anyagricultural operation. With increases in the toxicity and cost of spraymaterials it becomes more and more essential to achieve uniformapplication and to avoid unwanted drift of the finely divided material.Thus, insufficient or too great application is of course wasteful of thematerial itself, but with many modern spray materials excessiveapplication can even damage the crop plant. Again many modern materialsare sufficiently hazardous that the operators must wear specialprotective clothing and take special handling precautions. Manyauthorities now have enforced regulations as to weather conditions inwhich spraying can take place; for example with some materials theProvince of Ontario, Canada, will not permit spraying if the wind speedis higher than 7 m.p.h. (11 k.p.h.) while with some chemicals it isconsidered imprudent to operate if the wind speeds are higher than 4m.p.h. (6.4 k.p.h.).

One particular form of skirt structure employed hitherto consists of aperipheral air bag or bags which are inflated by the pressurised air.One of the problems encountered with any type of air-supported vehiclehitherto is the relatively high cost of the air-enclosing skirt, and itis a constant endeavour to provide as inexpensive a construction aspossible.

DEFINITION OF THE INVENTION

It is an object of the invention to provide a new spraying apparatusproviding for substantially complete enclosure of the spraying zone.

It is a further object to provide a new spraying apparatus in which thesprayer boom is supported from the ground by an air bag skirt enclosingthe spraying zone.

In accordance with the present invention there is provided sprayingapparatus employing a skirt structure comprising a sprayer boom frame, abag skirt structure carried by the frame and when inflated extendingdownwards therefrom to have its smoothly contoured convex lowermostportion in close proximity to the ground, the bag skirt structureforming an enclosure which is open to the ground, means for injectingair under pressure into the bag skirt and into the skirt enclosurewhereby the bag skirt is inflated and the boom and the skirt structurewill be supported above the ground and can be moved over the ground, anddispensing means mounted by the boom to deliver spray material to theskirt interior.

Preferably the bag skirt structure comprises two spaced parallelair-receiving passages constituting respective parts of an air bag orbags, and an end closure member comprising an envelope disposed over theadjacent ends of the said spaced parallel passages and overlapping saidends, wherein the air received in the passages expands the respectiveportions of the passages within the envelope into sealing engagementwith the envelope. Such a bag skirt construction preferably includesfastening means fastening a portion of the said passages to a portion ofthe envelope to retain the envelope thereon.

DESCRIPTION OF THE DRAWINGS

A spray apparatus employing an air bag structure which is a particularpreferred embodiment of the invention will now be described by way ofexample, with reference to the accompanying diagrammatic drawingswherein:

FIG. 1 is a general perspective view showing the spray apparatustogether with a liquid supply tank and tractor therefor;

FIG. 2 is a similar view to a larger scale showing the spray apparatusand a part only of the liquid supply tank;

FIG. 3 is a plane cross-section on the line 3--3 of FIG. 2;

FIG. 4 is a perspective view from below of part of the spray apparatuswith part of one of the skirt bags shown broken away to reveal the spraynozzles;

FIG. 5 is a plane section on the line 5--5 of FIG. 4 to show the mannerof mounting a nozzle;

FIG. 6 is a plane section on the line 6--6 of FIG. 4 to show the mannerof mounting a nozzle support;

FIG. 7 is a cross-section taken on line 7--7 of FIG. 2;

FIG. 8 is an exploded view of the end of the bag skirt; and

FIG. 9 is a cross-section on the line 9--9 of FIG. 2.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A complete agricultural sprayer consists of a tractor 10 (FIG. 1)pulling a liquid supply tank 12, which in turn tows behind it the sprayapparatus 14. In other embodiments the liquid supply tank can be mountedon the tractor which tows the apparatus 14 directly via the usual threepoint hitch. More particularly the tank 12 is provided at its rear endwith a small hoist derrick 16 on which is mounted a winch 18. The winchcable 20 is fastened by chains to the top of a circular fan housing 22mounting a fan 24. In this embodiment the fan housing is connected bysupport chains 26 (FIGS. 7 and 9) and a flexible tubular plenum member28 to a rectangular metal frame member 30. The fan 24 is driven, as isalso the winch 18, by power supplied in any well known manner from thetractor. It will be apparent that the weight of the spray apparatus 14is thereby minimized, as many as possible of the parts of the completesprayer being carried by the tractor 10 and/or the tank 12.

The housing frame member 30 is pivotally connected by rigid draw struts32 (FIG. 2) to the rear end of the tank 12 and serves as the convenientanchor point for two oppositely-extending spray boom frames, each ofwhich consists of two spaced parallel rods 34 connected together byspaced parallel cross-members 36. In this embodiment each rod 34 isdivided about mid-way of its length into two sections 34a and 34bpivotally hinged to one another at 38, while the inboard rod sections34a are pivotally hinged at 40 to the frame member 30, so that forstorage and transport each boom can be folded with the sections 34aextending upwards and the sections 34b extending downwards close andparallel to the sections 34a. This lifting into the storage andtransport position is effected by means of respective winches 42 mountedon the hoist 16 and connected by cables 44 to a respective cross member36. It will be appreciated that in other embodiments the rods may bedivided into more than two sections suitably pivoted to one another. Thehinges at 38 permit the above-described folding, and sufficient upwardhinging for the boom to be able to follow the ground directly underneathit. The hinges at 40 must of course permit ninety degree movement of thebooms upward, together with a smaller but sufficient downward movement.The spray boom frames are completed by arcuate front and backdownward-extending sections 46 hinged at 48 to the rods 34 to permitupward movement for storage, as illustrated by FIG. 3.

The spray boom frames hold a peripheral flexible bag skirt structure 50in extension, and are in turn supported by the skirt structure from theground under the effect of the air that is injected under pressure bythe fan 24 into an enclosure 52 formed by the skirt. In this particularembodiment the bag skirt is formed from an elongated strip of suitablematerial, e.g. heavy polyvinyl sheet, by folding the edge portions ofthe sheet toward its centre and fastening them to the centre part of thebody along spaced parallel lines, as at 54 in FIGS. 3 and 7. As bestseen in FIGS. 3, 4, 7 and 8 there are thus formed two elongated,parallel enclosed passages 56 each of which is supplied with air fromthe fan via respective openings 58 (FIG. 7) in the floor of the frame30. The passages are physically connected by the centre portion 60 ofthe elongated strip constituting a roof for the spray zone enclosure 52,this enclosure having the two air passages 56 as its respective longerside walls, and into which air is fed from the passages via apertures 62and 64 in the passage inside walls. Such a skirt is commonly called abag skirt in that it consists either of a single peripheral bag, oralternatively of a number of bags arranged around the periphery of thestructure to be supported thereby. The bag skirt structure is connectedto the rods 26a and 26b and frames 46 by loops 66 of the flexible skirtmaterial through which the frame rods are threaded.

Since in this embodiment the bag skirt is required to enclose a sprayzone constituted by the enclosure 52, it is desired that it besubstantially continuous around the periphery of the enclosure, anddifficulty has always been experienced hitherto in providing arelatively inexpensive method of forming the bag ends of a bag skirt. Inaccordance with this invention such end closures are provided by meansof two open-sided envelopes 68 which are slipped over the respectiveends of the above-described strip-formed passages. A rigid batten 70 isprovided on the upper surface of the strip mounted within a sleeve 72,and is of sufficient length to hold the bags to the required shape atthe respective locations. The central portion of the envelope lower edgecarries a shorter rigid batten 74 on a sleeve 76, which is then liftedup into the enclosure until it touches the roof underside; the twobattens 70 and 74 are then fastened together by lashings 78 (FIG. 2)passing through the roof around the battens. A substantial overlap isprovided between each envelope and the adjacent portion of the strip andit is found that, as the passages 56 are inflated they expand inside theenvelope and hold it sufficiently firmly to be retained without anysubstantial leakage during normal operating conditions.

Such an end closure avoids the need for relatively expensive seaming andjoining operations between the passage-forming strip and the end-closingenvelopes. It will be seen that the passage structure can readily beformed continuously, the desired length cut therefrom as required andthe end closures applied. If the air-sealing between the passagestructure and the end closures is not quite sufficient it can beimproved by making the latter of just slightly smaller periphery thanthe former, so that they are forced into even more intimate contact bythe internal air pressure.

As described above, each pair of parallel rods 34a and 34b is connectedby cross-members 36, the ends of which are removably fastened to therespective rods, so that the boom can readily be disassembled forremoval of the skirt. Each cross-member 36 has at its centre adownwardly-extending U-bolt clamp 80, the legs of which pass throughapertures in the enclosure roof 60, flanges 82 being provided on thebolt legs against which the material is clamped to permit an air-tightseal to be maintained where the legs pass through the material.L-section spray nozzle support member sections 84a and 84b are fixed tothe bights of the respective clamps, separate sections being used topermit the above-described folding for storage, etc. A plurality ofspray-nozzles 86 are mounted on each support member 84 so as to beadjustable in position along its length, permitting the nozzles to belocated as required relative to the rows of the crop to be sprayed. Thuseach nozzle is fastened to a bracket 88 (FIG. 5) which embraces thelower horizontal leg of the support, and can be clamped thereto by a setscrew 90. The nozzles are supplied with spray liquid or finely powderedmaterial under pressure from the tank 12 via flexible connecting hoses92 (not shown in FIGS. 1 & 2).

In operation, with the fan housing 22 suspended at a suitable heightfrom the derrick 16, the fan 24 is started and the skirt air bagsinflate, the air discharging into the enclosure 52 through the apertures62 and 64, as indicated by the arrows 94 in FIG. 3. The arcuatedownwardly-extending frame portions 46 support the sides of the inflatedbags as the sprayer is moved forward or backward. Thus the weight of thespray apparatus 14 is supported by the pressurized air with the loweredge of the bag skirt structure sufficiently close to the surface overwhich it is passing to brush it, so that a minimum of the air escapesfrom the enclosure 52, minimizing both the power required to pressurizethe air and the possibility of drift of air entrained material from theenclosure. The amount of air escaping will increase with increasing"porosity" of the surface to the outgoing air, due for example to thepresence of a growing crop, as the boom pulled behind the tractor passesover the rows of crop being sprayed, but this escape is downward intothe porous surface again minimizing sideways drift.

In this particular embodiment the pressurised air is fed first to theinterior of the bag skirt structure and thereafter to the enclosure 52,but in other embodiments the bag skirt structure may be pressurisedseparately.

The direction of movement of the boom is indicated by the arrow 96 inFIG. 3, and it will be noted that the aperture 62 in the leading passage56 is disposed relatively close to the ground, while the aperture 64 inthe trailing passage 56 is located close to the enclosure roof 60. Itwill also be noted that the effect of the passage of the apparatus overthe crop is to bend the plants in the direction of movement. Theenclosure 52 provides a virtually wind-free volume into which the sprayis directed, the major part constituted by the larger dropletsdischarging downwards, as with a conventional spray boom, so as to coatthe uppermost surfaces of the crop and the ground directly below. Aminor part constituted mainly by the smaller droplets will be entrainedby the air streams from the apertures 62 and 64 to be deposited on thecrop under surfaces. The forward aperture should also be the loweraperture to optimise this effect on the forward-bending crop. Thiseffect ensures to a much greater extend than is possible with unenclosedsprays that the plants are fully and uniformly exposed to the spraymaterial. Nevertheless, little or no spray material can escape from theenclosure.

The apertures 62 and 64 can consist of a large number of smallclosely-spaced holes, formed directly in the material of the bag skirt,but conveniently they are elongated slots, as illustrated, with theparallel edges connected by elongated strips 98 of mesh material throughwhich the air can flow. With this particular structure the air is fedinto the enclosure 52 uniformly from the front and rear air bags overthe entire length of the boom, to reduce as much as possible undesiredtransverse movement of the air in the enclosure, such transversemovement causing distortion of the spray pattern.

It will be understood that the profile of a bag skirt structure mustalways be a smooth curve providing for smooth and progressive entry andexit of the crop to and from the skirt enclosure, minimizing damage tothe crop over which it is passing. This must be contrasted with theeffect that would be obtained with a vertical skirt, the lower edge ofwhich would act as a form of scraper blade with its potential damage,particularly to a tender new crop. Furthermore, this shape incooperation with the surface over which it passes constitutes a diffuserpassage of progressively increasing area to the escaping air, so thatthe air discharge velocity drops abruptly immediately after passingthrough the narrowest part of the passage. The support of the apparatusboom in this manner ensures that the weight of each boom is uniformlydistributed over a substantial area and there is no need for outriggerwheels, with their possibility of damage. The winch 18 can be adjustedat any time to adjust the height of the fan housing 22 above the ground.The use of an air-supported structure is found to result in an"averaging" effect upon the height of the spray dispensing nozzles abovethe ground, and this is believed to be of importance in achieving animproved consistent spraying effect. Thus, in conventional wheeledapparatus adjacent wheels may be down in rut, hole or furrow and on topof a mound or hillock, so that the height of the respective nozzles isvery different. Again the too-fast travel of prior art apparatus overrough ground causes whipping movement of the boom, both vertically andlaterally, destroying the uniformity of the spray pattern. With theapparatus of the invention such changes in ground contour are averagedover the length of the boom to a much more constant value and boomwhipping is eliminated.

This maintenance of the spray dispensers at a substantially constantheight above the ground, gives a uniform spray pattern, as is desiredwith many modern materials where the rate of application must be closelycontrolled for most effective results. Since the spray material isdischarged into an effectively almost-fully-closed enclosure there isconsiderably reduced possibility of spray drift, and the small ratefound is in any case virtually independent of wind conditions, so thatspraying can be done under any conditions in which the air bags formingthe skirt remain sufficiently stable despite their quite high "windage".In this respect it may be noted that when the wind has an appreciable"following" component the links 20 may be under compression, since thebooms may be blown toward the tractor faster than they are being pulled.

Again owing to the physical characteristics of this new spray apparatus,and particularly the manner in which it is supported from the ground, itis possible to use relatively long booms, and apparatus of a totallength of 200 feet (60 meters) is readily operable. Moreover, theapparatus can be moved over the crop at relatively higher speeds, sinceit does not create its own "windage" in its passage, remembering thevery low wind speeds that are recommended for many modern materials.With the construction illustrated the skirt is readily removed fortransportation and storage of the apparatus, and can easily be replacedin case of damage and/or wear.

In some embodiments of the invention only apertures 62 may be providedin the leading passage, while the trailing bag passage is pressurisedbut air is not allowed to pass from the trailing bag passage to theenclosure 52. This arrangement can give the required spraying but ismore economical in the amount of pressurised air that is required.

Although the invention has been described as applied to an agriculturalsprayer, it will be apparent to those skilled in the art that it isapplicable to other spraying operations in which the close confinementof the spray material and/or removal of the need for outrigger supportsrunning on the ground are desirable features.

I claim:
 1. Spraying apparatus employing a skirt structure comprising:asprayer boom frame, a bag skirt structure carried by the frame and wheninflated extending downwards therefrom to have its smoothly contouredconvex lowermost portion in close proximity to the ground, the bag skirtstructure forming an enclosure which is open to the ground, means forinjecting air under pressure into the bag skirt and into the skirtenclosure whereby the bag skirt is inflated and the boom and the skirtstructure will be supported above the ground and can be moved over theground, said air bag structure comprising at least one air bag, theinner wall or walls of which comprise respectively the correspondinginside parallel leading and trailing wall parts or leading and trailingwalls of the enclosure, and into which air bag or bags the air isinjected under pressure and from which air passes into the enclosure,the said air passing from the said bag skirt structure into theenclosure via aperture means in the air bag or bags inner wall parts orwalls respectively, each such aperture means extending the full lengthof the respective air bag inner wall part or wall, wherein an aperturemeans in the leading inner wall part or leading inner wall is disposedclose to the ground, while an aperture means in the training inner wallpart or trailing inner wall is disposed closely adjacent to a roof ofthe enclosure, and dispensing means mounted by the boom frame to deliverspray material to the skirt enclosure.
 2. Spraying apparatus as claimedin claim 1, wherein each said aperture means is constituted by arespective elongated slot in the wall part or wall, the parallel edgesof which are connected by an elongated strip of mesh material throughwhich the air flows.
 3. Spraying apparatus as claimed in claim 1,wherein said means for injecting air comprises a fan in a fan housingconnected to the bag skirt and the enclosure by a flexible tubularpassage member through which air passes from the fan to the bag skirtand the enclosure, and including means for supporting the weight of thefan and the fan housing independently of the sprayer boom frame. 4.Spraying apparatus as claimed in claim 1, wherein the sprayer boom framecomprises at least two hingedly-connected boom portions, whereby eachboom portion can be moved from an extended horizontal operative positionto a folded storage position in which the boom portions extendapproximately vertical and parallel to one another.
 5. Sprayingapparatus as claimed in claim 4, wherein the sprayer boom framecomprises two spaced parallel rods connected together along its lengthby cross-members, and the bag skirt structure is supported from theframe by means of loops of material fastened to the skirt and throughwhich the rods are threaded.
 6. Spraying apparatus as claimed in claim5, wherein said sprayer boom frame includes arcuate downwardly-extendingmembers engaging the exterior surfaces of the bag skirt structure forsupport thereof.
 7. Spraying apparatus as claimed in claim 1, whereinthe sprayer boom frame comprises two spaced parallel rods connectedtogether along its length by cross-members, and the bag skirt structureis supported from the frame by means of loops of material fastened tothe skirt and through which the rods are threaded.
 8. Spraying apparatusemploying a skirt structure comprising:a sprayer boom frame, a bag skirtstructure carried by the frame and when inflated extending downwardstherefrom to have its smoothly contoured convex lowermost portion inclose proximity to the ground, the bag skirt structure forming anenclosure which is open to the ground, means for injecting air underpressure into the bag skirt and into the skirt enclosure whereby the bagskirt is inflated and the boom and the skirt structure will be supportedabove the ground and can be moved over the ground, said means forinjecting air comprising a fan in a fan housing connected to the bagskirt and the enclosure by a flexible tubular passage member throughwhich air passes from the fan to the bag skirt and the enclosure, meansfor supporting the weight of the fan and the fan housing independentlyof the sprayer boom frame, and dispensing means mounted by the boomframe to deliver spray material to the skirt enclosure.
 9. Sprayingapparatus as claimed in claim 8, wherein the said fan in the fan housingis supported above the sprayer boom, frame and is connected to the bagskirt and the enclosure by a downwardly-extending tubular passagemember.
 10. Spraying apparatus as claimed in claim 8, wherein the saidbag skirt structure comprises at least one air bag, the inner wall orwalls of which comprise respectively the corresponding inside parallelleading and trailing wall parts or leading and trailing walls of theenclosure, and into which air bag or bags the air is injected underpressure and from which air passes into the enclosure.
 11. Sprayingapparatus as claimed in claim 10, wherein the air passes from the saidbag skirt structure into the enclosure via aperture means in the air bagor bags inner wall parts or walls respectively, each such aperture meansextending the full length of the respective air bag inner wall part orwall.
 12. Spraying apparatus employing a skirt structure comprising:asprayer boom frame, a bag skirt structure carried by the frame and wheninflated extending downwards therefrom to have its smoothly contouredconvex lowermost portion in close proximity to the ground, the bag skirtstructure forming an enclosure which is open to the ground, means forinjecting air under pressure into the bag skirt and into the skirtenclosure whereby the bag skirt is inflated and the boom and the skirtstructure will be supported above the ground and can be moved over theground, and dispensing means mounted by the boom frame to deliver spraymaterial to the skirt interior, wherein the sprayer boom frame comprisesat least two hingedly-connected boom portions, whereby each boom portioncan be moved from an extended horizontal operative position to a foldedstorage position in which the boom portions extend approximatelyvertical and parallel to one another.
 13. Spraying apparatus as claimedin claim 12, wherein the sprayer boom frame comprises two spacedparallel rods connected together along its length by cross-members, andthe bag skirt structure is supported from the frame by means of loops ofmaterial fastened to the skirt and through which the rods are threaded.14. Spraying apparatus as claimed in claim 13, wherein said sprayer boomframe includes arcuate downwardly-extending members engaging theexterior surfaces of the bag skirt structure for support thereof. 15.Spraying apparatus employing a skirt structure comprising:a sprayer boomframe, a bag skirt structure carried by the frame and when inflatedextending downwards therefrom to have its smoothly contoured convexlowermost portion in close proximity to the ground, the bag skirtstructure forming an enclosure which is open to the ground, means forinjecting air under pressure into the bag skirt and into the skirtenclosure whereby the bag skirt is inflated and the boom and the skirtstructure will be supported above the ground and can be moved over theground, dispensing means mounted by the boom frame to deliver spraymaterial to the skirt interior, and wherein the sprayer boom framecomprises two spaced parallel rods connected together along its lengthby cross-members, and the bag skirt structure is supported by the frameby means of loops of material fastened to the skirt and through whichthe rods are threaded.